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Uncertainty in Medicine

snowball
Medicine is an uncertain business. It is an applied science, applying the results of basic science knowledge and clinical studies to patients who are individuals with differing heredity, environment, and history. It is commonly assumed that modern science-based doctors know what they are doing, but quite often they don’t know for certain. Different doctors interpret the same evidence differently; there is uncertainty about how valid the studies’ conclusions are and there is still considerable uncertainty and disagreement about things like guidelines for screening mammography and statin prescriptions.

Snowball in a Blizzard by Steven Hatch, MD, is a book about uncertainty in medicine. The title refers to the difficulty of interpreting a mammogram, trying to pick out the shadows that signify cancer from a veritable blizzard of similar shadows. (more…)

Posted in: Book & movie reviews, Science and Medicine

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The Fog of Medicine

autism biomed

Sometimes medicine is a little like this.

I often get called on to be a diagnostician. The referring doctor is uncertain what is going on in the patient, often a fever of unknown origin, and they call me to help figure it out. Sometimes I do, sometimes I don’t.

Making the correct diagnosis is not easy, even after 35 years. The classic phrase is the fog of war, but the fog of medicine is equally confusing. In retrospect sometimes a diagnosis becomes clearer, but in real time? It is so easy to be wrong and so difficult to be correct.

I remember the first case of my career. A patient developed neutropenia (low white count) from a sulfa antibiotic and over the next two weeks went into multi-organ system failure and died. At autopsy it was discovered that he had miliary tuberculosis. I totally missed the diagnosis, despite all the tests, including liver and bone marrow biopsies before he died.

A decade later a case was presented at conference about a patient with a fever who went into multi-organ system failure and died. At the time of the conference I had zero recollection of the case from a decade earlier, but knew this was a case of miliary TB based on the data presented, although it was far from a textbook case. After the conference the presenter let me know that it had been my case, the one I had missed years ago.

I was ten years wiser in my medical career and more aware of the subtleties and variations of disease presentation. Experience has made me a somewhat better diagnostician. Or so I hope. Making the diagnosis of a common presentation of a common disease should be simple, but patients rarely read the textbooks and we are more likely to see an uncommon presentation of a common disease, a common presentation of an uncommon disease, and most dreaded, an uncommon presentation of an uncommon disease. (more…)

Posted in: Critical Thinking

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IOM Recommends Replacing CFS with SEID

Exertion intolerance

Exertion intolerance

Chronic fatigue syndrome (CFS) is a controversial diagnosis that has also been called myalgic encephalomyelitis (ME or ME/CFS), post-viral fatigue syndrome (PVS), chronic fatigue immune dysfunction syndrome (CFIDS), Iceland disease, “yuppie flu,” and many other names. A new report from the Institute of Medicine (IOM) says that none of those names really fit the disease and recommends it be re-named systemic exertion intolerance disease or SEID.

ME/CFS is thought to affect as many as 2.5 million Americans. The cause remains unknown, but in many cases it appears to have been “triggered by an infection or other prodromal event, such as immunization, anesthetics, physical trauma, exposure to environmental pollutants, chemicals and heavy meals, and rarely blood transfusions.” Some doctors question its very existence and interpret the symptoms as imaginary or psychological.

The IOM examines the evidence base

At the request of several government agencies including the NIH and the FDA, the IOM convened a committee of 15 experts to examine the evidence base for ME/CFS. They reviewed over 9,000 published studies and heard testimony from patients and advocates. Before publication, an additional 15 experts were asked to provide peer review. The full text of the report is available free online. (more…)

Posted in: Science and Medicine

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Diagnosis, Therapy and Evidence

When Dr. Novella recently wrote about plausibility in science-based medicine, one of our most assiduous commenters, Daedalus2u, added a very important point. The data are always right, but the explanations may be wrong. The idea of treating ulcers with antibiotics was not incompatible with any of the data about ulcers; it was only incompatible with the idea that ulcers were caused by too much acid. Even scientists tend to think on the level of the explanations rather than on the level of the data that led to those explanations.

A valuable new book elaborates on this concept: Diagnosis, Therapy and Evidence: Conundrums in Modern American Medicine, by medical historian Gerald N. Grob and sociologist Allan V. Horwitz. They point out that 

many claims about the causes of disease, therapeutic practices, and even diagnoses are shaped by beliefs that are unscientific, unproven, or completely wrong. (more…)

Posted in: Book & movie reviews, Science and Medicine

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Diagnostic Dilemmas

Sometimes diagnosis is straightforward. If a woman has missed several periods and has a big belly with a fetal heartbeat, it’s pretty easy to diagnose pregnancy. But most of the time diagnosis is much more difficult. Alzheimer’s can’t be diagnosed for sure until the patient dies and you do an autopsy. If only we had one of those Star Trek gadgets to point at our patients and give us a quick and accurate answer! Alas! We are far from perfect. All too often, we really have no idea what’s causing a patient’s symptoms. We do a complete workup and still don’t know. What then?

We all know people who have symptoms that a series of doctors have failed to diagnose, who continue to doctor-shop, hoping to find that one doctor somewhere who will find something the others have missed. Occasionally they do; but far more often these people spend a great deal of time and money chasing a will-o’-the-wisp. Sometimes as they are searching, the illness gradually runs its course and goes away. When this happens, whatever they tried last gets the undeserved credit for the “cure.” Sometimes the symptoms persist and these searches consume their life, encourage unhealthy self-absorption, and permanently ensconce them in the “sick” role.

One of the attractions of alternative medicine is that it offers far more certainty than scientific medicine. If your scientific doctor can’t see anything on x-rays, your chiropractor can. He’ll tell you he knows exactly what’s wrong: a subluxation that he can fix. Sherry Rogers will tell you all illness is due to toxins accumulating in your cells and you must “detoxify or die.” Hulda Clark will tell you it’s all parasites that she can eliminate with her magic zapper. Robert Young says the cause of all disease is acidosis. They all have confident, precise answers. Wrong ones.

The One Cause of All Disease?

It’s really easy to figure out what’s causing a patient’s symptoms if you believe there is one simple cause for all disease. While I was writing this I got sidetracked and searched the Internet for “the one cause of all disease.” I found a lot of them, including: (more…)

Posted in: Diagnostic tests & procedures, Science and Medicine

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